The present invention relates to an apparatus for monitoring an ignition lock and doors and warning the vehicle operator if it appears that he may be leaving an ignition key in the ignition lock while exiting the vehicle.
Many automotive vehicles provide the vehicle operator with an audible key chime to remind him that the ignition key has been left in the ignition when his door is open. In vehicles employing such a system, a mechanical contact physically touches the key to determine if the key is still in the ignition lock.
One disadvantage of present implementations of key-in-ignition sensing is that the mechanical contact employed has a high failure rate due to oxidation of the contacts. Another disadvantage is the increased complexity of an ignition switch which incorporating the mechanical key-in-ignition contact and its associated wiring.
Some vehicles have anti-theft systems using a transponder carried on a key to identify that an unauthorized key has been placed in the ignition before allowing a vehicle to start. One disadvantage of such systems is that if the engine does not start, the operator does not know whether it is the engine or the anti-theft system that is malfunctioning.
It would therefore be desirable to eliminate the mechanical key-in-ignition mechanical switch and still provide the function of a key-in-ignition warning system.